So Javascript just wants to join in on the OOP club?

As far as i know, because this one is still considered as an object, where you can directly write function rather than declaring 'class' first, it is also known as Constructor Function.

Nobody's going to change the kata requirements after 13k completions.

In the solution, .reduce(:&) could be replaced with .all?.

From the instructions:

Note that leading zeros (e.g. 01.02.03.04) are considered invalid.

FWIW, in real life leading zeros are valid in an IP address (try pinging 127.000.000.001).

I'm not disagreeing with you because I'm still learning JS, but as a programmer that seems wrong to me. Since you can't confirm what type the input will be, wouldn't it be best to check against undefined rather than your method? I mean again, it's clever - but would you really want to use it in production? Is it faster to make sure the input isn't falsy, AND use the code above?

Very clever, but is this a best practice? It's not immediately clear what's going on, whereas the other solutions are.

Absolutely true!!
I am learning this now and I dont know a hell of it :)

thanks for thinking in us :))

I had opened a tab with MDN JS docs to read through for the explanation you gave here. thanks ^ ^